1. Field of the Invention
The invention relates to the field of automatic guns using belted ammunition and more particularly to stripping mechanisms for removing the ammunition from the ammunition belt with a side thrusting force.
2. Description of the Prior Art
Ammunition is typically handled and loaded into automatic guns and cannons with the use of link belts from which the ammunition is stripped by the feeding or loading mechanism of the automatic gun. Typical examples of such linked belts are shown by Zehnder, "Automatic Firearm Feed Mechanisms", U.S. Pat. No. 3,229,584 and by Skahill, "Cam Actuated Ammunition Pre-Stripping Mechanism", U.S. Pat. No. 4,290,339. However, many prior art mechanisms for stripping ammunition from linked belts provide a push or pull approximately aligned with the longitudinal axis of the round. In other words, a force is applied to the end of the round casing pushing the round from the link across the length or longitudinal axis of the link. Such end stripping mechanisms require some type of pushrod which can exert a force on the round across a distance long enough and far enough to fully displace the round from the link. In addition, the frictional force exerted by the resilient fingers of the link which usually tightly clasp the round, is fairly substantial. Therefore, end strippers tend to be the slowest component of the automatic gun, tend to limit its firing rate, and also tend to require substantial amounts of power to operate.
In an attempt to overcome these shortcomings, various prior art designs have been developed to side strip the ammunition from such belts. Typically, the link enclosing the round is generally C-shaped in cross section and thereby provides resilient fingers as the arms of the "C" which tightly clasp the round. The transverse opening of the C-shaped link provides a means of exit for the round. Various types of mechanisms have been devised for applying a force to the round in order to force the round through the transverse opening of the link. One example of such mechanisms is shown in Darsie, "Means for Stripping Links in a Firearm", U.S. Pat. No. 2,789,474. In Darsie, a fixed spearing cam penetrates a specially designed link through an opening provided along the backbone of the link opposite the transverse opening of the link. The cam surface provides a curved surface against the back of the round so that as the link belt is advanced, the round is urged through the transverse opening of the link by the curved surface of the fixed spearing cam, which surface leads in a direction away from the link while the link continues in a predetermined direction. An additional example of such mechanisms is shown in Rocha, "Cartridge Feed, Positioning and Injection Control System", U.S. Pat. No. 4,038,904 wherein an oscillating finger contacts the back of the round and moves through an open space provided in the link forcing the round from the link or conveyor belt into the breech and then returns to its original position behind the link or belt.
However, each of these mechanisms are still subject to the shortcoming that frictional forces are developed in a direction which does not serve to strip the round from the belt. Generally, such side stripping forces have a component at some point during the stripping operation acting in a direction which does not directly extend through the longitudinal axis of the round. These nonaxially aligned forces exert a pressure against the resilient fingers of the C-shaped link and therefore exert a torque on each link at some point in time. The torque causes the link to twist which can sometimes be so severe that the link and the belt will jam within the gun or deform the resilient fingers of the link. The deformed link might then jam within the gun or at least tend to cause the round to be delayed or tilted in an unanticipated direction in the feed mechanism thereby causing the round to possibly jam the gun or interfere with its smooth operation. These complications are particularly aggravated where the stripping force must be applied to the round within a short time interval as in Rocha and thereby tends to be impulsive.
What is needed then is some type of mechanism for side stripping ammunition from linked belts which overcomes each of these shortcomings, namely, which is capable of smoothly removing the round from the belt without twisting the belt or bending and deforming the link.